If you have original Medicare, the answer is easy: you can travel anywhere in the U.S. or its territories and receive health services from any doctor or hospital that accepts Medicare. (“Territories” includes Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands.) The amount you will pay depends on whether the provider “accepts assignment.” Those that take assignment agree to accept the approved Medicare amount as payment in full, although in the case of outpatient visits you or your Medigap insurer may be left with a 20 percent coinsurance, as would be the case for care at home.

Providers that don’t accept assignment may charge you up to 15 percent above the Medicare-approved amount, although this percentage may be lower in some states. In the case of providers that don’t accept Medicare at all, you will have to pay the entire cost of care.

If instead of original Medicare you are in a Medicare Advantage plan (a privately run managed care plan), the answer to the question of coverage is more complicated. Depending on your post-retirement goals, this could be a consideration in whether you choose original Medicare or an Advantage plan.

For enrollees traveling for less than six months outside their plan’s service area, Medicare Advantage plans must cover emergency and urgent care, and charges for such care that is out-of-network cannot exceed $65 or whatever you would have paid for an in-network provider. Whether you will be covered for anything more than emergency or urgent care depends on the plan’s geographic service area, its rules about travel outside of that area, and what type of plan it is.

If your plan is of the PPO (Preferred Provider Organization) variety, it must cover care delivered by providers who aren’t in the plan’s network or service area, although you will usually pay more for out-of-network care. Plans that follow the HMO (Health Maintenance Organization) model usually do not cover care from out-of-network providers. If your HMO plan does cover out-of-network providers, be sure to follow the plan’s rules or you may find that you’re not covered, and you will likely pay more for the care in any case.

If you are outside your plan’s service area for six months or more, most plans must automatically disenroll you and you will be returned to original Medicare unless you choose another Medicare Advantage plan. However, some plans will allow you to travel outside the service area for up to a year. Even if your plan has such a travel benefit, check what geographic areas and types of care are covered. If you get care from providers not covered in the plan’s network, you may pay more or not be covered at all.

The Medicare Rights Center advises Medicare Advantage enrollees to “look at your plan benefits carefully to see what costs and rules apply when you travel within the United States or its territories.” For more from the Medicare Rights Center on Medicare Advantage coverage if traveling within the U.S., click here.

If your plan denies you coverage, you can always appeal. For more on Medicare Advantage appeals, click here.